This application is not related to any pending United States or international patent application. This application is not referenced in any Microfiche Appendix.
This disclosure is to a system and a method for separating an entrained immiscible liquid component from a gas stream.
The subject of the invention generally relates to gas/liquid (2 phase) separators or gas/liquid/solid (3 phase) separators. The invention may also be practiced in which the liquid phase is a mixture of an aqueous phase and an organic or hydrocarbon phase. Separators of this type are typically process vessels that may be at atmospheric or above atmospheric pressure. The main function of the separator system is to segregate immiscible phases of a process stream. The process stream may be in the form of gas that carries with it an immiscible liquid component, frequently referred to as a xe2x80x9cwet gasxe2x80x9d stream. The function of the separator of this invention is to separate out the liquid component to provide at the output of the separator a xe2x80x9cdry gasxe2x80x9d streamxe2x80x94that is, a gas stream that is relatively free from entrained liquids.
The systems and method of this disclosure are basically applicable to: (1) removing liquid dispersed in a gas stream, such as in which the liquid is of relatively little volume compared to the gas and in which the liquid may be primarily in the form of mist; and (2) removing gas from a liquid stream in which the gas is of a relatively small proportion (by weight) of the stream. In the first instance the separation process is generally referred to as xe2x80x9cgas demistingxe2x80x9d and in the second instance the separation process is generally referred to as xe2x80x9cliquid degassingxe2x80x9d.
Separators for separating liquid components from a gas stream are commonly utilized in the oil and gas industry, specifically in oil and gas production, oil refining and gas processing, and are also used in the mining industry, chemical plants, water treatment facilities, pulp and paper plants and pharmaceutical manufacturing facilities.
Separation of immiscible components of a wet gas stream usually depends on the force of gravity. Gravity can be either natural gravityxe2x80x94that is, the pull of mass towards the center of the earth or created (artificial) gravitational forces such as represented by centrifugal separators. Natural gravity is usually used by flowing a stream having immiscible components into a vessel which provides a quiescent zonexe2x80x94that is, a relatively undisturbed environment that allows gravity to act on heavier components of the stream and move them into a downward part of the vessel. This movement has the counteraction of the lighter components of the stream migrating to an upward part of the vessel. In this way, the heavier componentsxe2x80x94that is, liquids, can be withdrawn from the lower part of the vessel and the lighter componentsxe2x80x94that is, gases, withdrawn from an upper part of the vessel.
Separators commonly have an inlet momentum absorber or deflector to reduce the momentum of the incoming stream and to distribute liquid and gas within the separator vessel. This kinetic energy reduction initiates phase separation inside a separator vessel.
Artificial gravity can be generated by the use of a vortex tube or tubes. A vortex tube is typically an elongated tube having a cylindrical interior wall that is preferably vertically mounted or at least mounted with a vertically downward tangent. The vortex tube (or each vortex tube if more than one is employed) has an inlet arranged so that wet gas flowing therein tangentially intersects the interior wall of the vortex tube and flows around the interior wall to thereby create centrifugal force that is applied to the components, the centrifugal force serving to move the heavier componentxe2x80x94that is, the liquid component, towards the wall of the vortex tube while the lighter component (gas) is forced towards the interior of the tube. In a typical vortex tube, the gas is withdrawn from an upper central vortex opening while the liquid component is withdrawn from a liquid outlet in the bottom portion of the tube.
This invention herein is a system and method employing a separator internal process apparatus in combination with a vortex tube or a xe2x80x9cvortex tube clusterxe2x80x9d. In a vortex tube cluster, each tube receives a portion of the incoming flow stream, which enters tangentially, creating rotation flow.
For additional background information relating to the general subject mater of this disclosure reference may be had to the following previously issued United States patents:
A better understanding of the invention will be obtained from the following description and claims, taken in conjunction with the attached drawings.
The invention herein of a method, and a system for practicing the method, of separating an entrained immiscible liquid component from a gas stream. The method includes the steps of introducing a wet gas stream into a wet gas inlet of a treatment vessel, the vessel having a dry gas outlet and a liquid outlet. The wet gas stream is passed into at least one vortex tube but in the preferred practice of the invention, into a cluster of vortex tubes. Whether one or a plurality of vortex tubes, the wet gas passes into an inlet thereof wherein the gas is caused to circumferentially swirl within cylindrical walls of the vortex tubexe2x80x94that is, the wet gas stream rapidly rotates. The rapid rotation causes the heavier, liquid component and any entrained solids, to be moved to the external circumference of the rotating gas stream. A dry gas opening is provided centrally within an upper portion of each vortex tube and a liquids/solids outlet is provided in a lower end of each vortex tube.
Liquids and any entrained solids that pass out the lower end of the vortex tube collect in a lower portion of the treatment vessel while the dry gas moves to an upper portion of the vessel. The extracted liquid along with any entrained solids is withdrawn from the vessel through the liquid outlet. The gas passing out of the vortex tube or tubes typically is not completely dry but is substantially drier than the wet gas that passes into the treatment vessel. The gas passing out of the vortex tube or tubes is passed through a mist interceptor within the vessel wherein any remaining liquid or at least a substantial part of any remaining liquid, is stripped from the gas before the gas passes out of the vessel through the dry gas outlet. The mist interceptor may be, as examples, in the form of:
(1) a vane-type mist eliminator;
(2) a mesh-type mist eliminator;
(3) a cartridge-type coalescing element;
(4) a filter element; or
(5) a pack or a dump-type coalescing element.
The invention may be practiced in vessels having various shapes including cylindrical vessels horizontally or vertically arranged. The mist interceptor may be arranged in a variety of locations within the vessel. Liquid extracted from the wet gas stream may be treated within the vessel by the use of perforated plates, packed coalescing elements and/or electrostatic fields.